Fix non-null check message in NativeFunctionDefinitionProvider

[pdabre12]

Description

Fix non-null check message in NativeFunctionDefinitionProvider

Contributor checklist

• Please make sure your submission complies with our contributing guide, in particular code style and commit standards.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• If release notes are required, they follow the release notes guidelines.
• Adequate tests were added if applicable.
• CI passed.

Release Notes

Please follow release notes guidelines and fill in the release notes below.

If release note is NOT required, use:

== NO RELEASE NOTE ==